I have completed it for you. I would have liked the detail to be a little clearer .
It would be helpful to know what specific information you are trying to gain from the questions.
For example had you said you were looking for a parents prospective on the reasons I believed my children chose their GCSE subjects then I would answer one way, you left it to me to decide how I answer so I took it that you meant why I chose the subjects I did when I was a student.
I chose my GCSE's for completely different reasons to that of my children. Mine were all on the whole compulsory. I took them the very first trial year as my school was part of the initial trial group. We were given only 2 options to choose from on top of the compulsory subjects. My choices were along the lines of which humanity do you want to study? RE, Geography or History? plus Which craft subject do you want to study? Home Economics, CDT or Art? That's it.
My children have what seems to be more than a dozen different subjects they can choose from including Engineering and Business Studies, Law etc.
You will struggle to make useful comparisons I think without making it clearer that you want modern day students experiences rather than their parents or you will need a way to separate the 2 experiences.